drm/i915: Add has_64k_pages flag

Add a new platform flag, has_64k_pages, to mark the requirement of 64K
GTT page sizes or larger for device local memory access.

Also implies that we require or at least support the compact PT layout
for the ppGTT when using 64K GTT pages.

v2: More explanation for the flag [Thomas]
Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211208141613.7251-2-ramalingam.c@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -1717,6 +1717,14 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 #define HAS_MSLICES(dev_priv) \
 	(INTEL_INFO(dev_priv)->has_mslices)
 
+/*
+ * Set this flag, when platform requires 64K GTT page sizes or larger for
+ * device local memory access. Also this flag implies that we require or
+ * at least support the compact PT layout for the ppGTT when using the 64K
+ * GTT pages.
+ */
+#define HAS_64K_PAGES(dev_priv) (INTEL_INFO(dev_priv)->has_64k_pages)
+
 #define HAS_IPC(dev_priv)		 (INTEL_INFO(dev_priv)->display.has_ipc)
 
 #define HAS_REGION(i915, i) (INTEL_INFO(i915)->memory_regions & (i))

drivers/gpu/drm/i915/i915_pci.c

@@ -1015,6 +1015,7 @@ static const struct intel_device_info xehpsdv_info = {
 	DGFX_FEATURES,
 	PLATFORM(INTEL_XEHPSDV),
 	.display = { },
+	.has_64k_pages = 1,
 	.pipe_mask = 0,
 	.platform_engine_mask =
 		BIT(RCS0) | BIT(BCS0) |
@@ -1033,6 +1034,7 @@ static const struct intel_device_info dg2_info = {
 	.graphics.rel = 55,
 	.media.rel = 55,
 	PLATFORM(INTEL_DG2),
+	.has_64k_pages = 1,
 	.platform_engine_mask =
 		BIT(RCS0) | BIT(BCS0) |
 		BIT(VECS0) | BIT(VECS1) |

drivers/gpu/drm/i915/intel_device_info.h

@@ -123,6 +123,7 @@ enum intel_ppgtt_type {
 	func(is_dgfx); \
 	/* Keep has_* in alphabetical order */ \
 	func(has_64bit_reloc); \
+	func(has_64k_pages); \
 	func(gpu_reset_clobbers_display); \
 	func(has_reset_engine); \
 	func(has_global_mocs); \